We investigate here
the strain-induced growth of Cu at 600 °C
and its interactions with a thermally grown, 270 nm-thick SiO2 layer on the Si(111) substrate. Our results show clear evidence
of triangular voids and formation of triangular islands on the surface
via a void-filling mechanism upon Cu deposition, even on a 270 nm-thick
dielectric. Different coordination states, oxidation numbers, and
chemical compositions of the Cu-grown film are estimated from the
core level X-ray photoelectron spectroscopy (XPS) measurements. We
find evidence of different compound phases including an intermediate
mixed-state of Cu–O–Si at the interface. Emergence of
a mixed Cu–O–Si intermediate state is attributed to
the new chemical states of Cu
x+, O
x
, and Si
x+ observed
in the high-resolution XPS spectra. This intermediate state, which
is supposed to be highly catalytic, is found in the sample with a
concentration as high as ∼41%. Within the Cu–O–Si
phase, the atomic percentages of Cu, O, and Si are ∼1, ∼86,
and ∼13%, respectively. The electrical measurements carried
out on the sample reveal different resistive channels across the film
and an overall n-type semiconducting nature with a sheet resistance
of the order of 106 Ω.